Yeah, the most interesting thing I see in this picture is how 'he' is extending along the back of the arms, note the flexed right wrist and how the fingers extend out. He seems to be drawing his body just like a bow and the ribcage is almost thrust forward. He is extending strongly through the legs. The bit that puzzles me is the almost casual way he is resting on the left hip.
Thanks, I spend long hours looking at the way people stand, that is actually quite interesting.